64 THE U. S. GEOLOGICAL SURVEY 



In the following year the Survey made recommendations 

 to the Secretary for the withdrawal of oil and gas lands, and 

 in 1909 of potash lands pending legislation for their disposi- 

 tion. In the same year the Survey's activities in this field 

 were extended to lands containing water-power sites and in 

 1 91 2 to public water reserves, that is, water supplies necessary 

 for the utilization of the public range, and still later to phos- 

 phate lands, oil-shale lands, and lands suitable for designation 

 under the enlarged homestead laws. All this classification 

 work was undertaken, and is still continued, without express 

 legislative warrant other than that contained in the original 

 act of 1879. In 1 91 7, however, Congress made an appropri- 

 ation of $150,000 "for the examination and classification of 

 lands requisite to the determination of their suitability for 

 enlarged homesteads, stock-raising homesteads, public water- 

 ing places, and stock driveways, as required by the public land 

 laws," — the first specific appropriation for land classification 

 work ever made to the Survey. 



Legal Provisions Applied in Land Classification. For an 

 understanding of the methods employed by the Survey in land 

 classification work, some knowledge is necessary of the provi- 

 sions of law towards the execution of which that work is 

 directed. These provisions are too numerous and intricate 

 for analysis here, but in their relation to the classification 

 problem of the Survey they may be said to fall into two 

 classes — those involving a determination of the mineral re- 

 sources of the particular tract involved, and those involving a 

 determination of its relation to the available water supply. In 

 the first class fall those provisions requiring a determination 

 as to whether the land contains minerals. If it does it is not 

 open to homestead entry nor may it be taken under a railroad 

 grant (unless it contains only coal and iron) or under a grant 

 to a state. It is open to entry only under special laws, which, 

 however, vary according as the land contains coal or other 

 minerals. In general, these special provisions affect only the 

 extent and character of the right acquired by the entryman or 



